This workshop is scheduled to be held June 6-10, 1999 at the Bet Gabriel Cultural Center in Israel. The objective of the workshop is to bring together investigators with a broad spectrum of research interests to discuss the current state of knowledge regarding Down Syndrome and human chromosome 21. Research perspectives are designed to encompass all relevant areas of biology, molecular biology and medicine as they pertain to increasing our understanding of the mechanisms leading to the phenotype of DS. The need for the workshop proposed here has grown from the enormous amount of new molecular, biological data that has developed for chromosome 21 as a result of the human genome initiative. Specifically complete genomic sequencing of 21q is in progress in a consortium of laboratories from Japan, Germany and the United States. Several megabases have already been completed and the entirety of 21q is projected to be completed by the time of this meeting 1999. As sequencing data accumulate, additional new genes and their complete coding sequences will be identified. Expression analyses and protein functional determinations will develop rapidly and concomitantly. It is anticipated that a workshop format will foster interaction across disciplines, help to focus and redirect research efforts for maximal use of developing data, and establish new collaborations and avenues of investigation.